The production of benzoic acids from phthalimides by hydrolysis/decarboxylation is a reaction of considerable commercial importance. The conversion of tetrafluorophthalimide to 2,3,4,5-tetrafluorobenzoic acid, a precursor in the synthesis of Floxacin antibiotics, is an example of the reaction's commercial application. The hydrolysis/decarboxylation reaction can be particularly applicable in cases in which a phthalic acid or phthalic anhydride is converted to a phthalimide in order to protect the diacid or anhydride functionality from being compromised by a process which alters the substituency of the adjacent aromatic ring. Such hydrolysis/decarboxylation can subsequently be implemented to obtain a benzoic acid with the altered ring substituency.
The currently practiced method for hydrolysis/decarboxylation has a serious deficiency in that the reaction requires extremely long reaction times in order to come to substantial completion. Reaction times on the order of days are commonly encountered. Such long reaction times can cause the production of benzoic acids from phthalimides to be the rate limiting step in the synthesis of some organic compounds.
A method of conducting the hydrolysis/decarboxylation which reduces the reaction time presently required for the completion of the reaction would be a welcome contribution to the chemical and pharmaceutical industries.